Bipolar Copolymers Comprised Mesogen-Jacketed Polymer Containing Oxadiazole Units and PVK as Host Materials for Electroluminescent Devices

摘要

Nonconjugated bipolar transport polymers have been developed as host materials for electroluminescent devices by incorporating both electron-tran sporting and hole-tran sporting functionalities into copolymers. The random copolymer PCt-nvk3-7 containing mesogen-jacketed segment of P-Ct have been synthesized and characterized. The effect of mesogen-jacketed segment content of these bipolar copolymers on device performance has been investigated. The results of polymer light-emitting diodes (PLEDs) show that the jacketed content of copolymers has a significant effect on device performance: lowering charge transport and facilitating the hole-electron recombination leads to much higher current efficiency. Applying these high triplet random copolymers as host, the maximum current efficiency of 0.70 cd/A and the maximum brightness of 1872.8 cd/m(2) was achieved for PCt-nvk3-7 with an orange-emitting complex dopant. The results suggest that the bipolar copolymers PCt-nvks can be good host polymers for electrophosphorescent devices. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7861-7867, 2008